Anyone else remember those “this is your brain on drugs” commercials? They’d hold an egg on screen and say, “This is your brain.” Then, after cracking it open and putting it into a sizzling hot frying pan, they’d continue, “This is your brain on drugs.” And finally, the kicker.

“Any questions?”

While the underlying message that drugs will mess up your brain is valid enough, scientists are still just beginning to understand exactly how the different chemicals affect one’s brain. And they certainly don’t all act the same.

Take cocaine, for example. One of the things cocaine does – among many – is affect the functioning of the dopamine receptor D5. Because dopamine is generated by the brain in order to experience pleasure and rewards, changing the receptor changes how much one experiences these pleasures. Thus, addicts are basically on a 24/7 pleasure cruise.

Well, so long as they keep the substance coming.

Nicotine works slightly differently, but also causes an excitability by neurons involved in reward. Learning and memory are thought to be encoded in the brain by the ability of neural synapses to adapt and change. Chemicals and experiences can change these long-term strengthening and weakening of connections between neurons. For example, when two neurons are repeatedly activated together, a stronger bond forms between them, increasing the ability of one to excite the other.

Previous research discovered that nicotine could promote the ability of these synapses to form stronger bonds in a region of the brain called the ventral tegmental area (VTA). Neurons that originate in the VTA release the dopamine known to play a central role in the effects of addictive drugs and natural rewards such as food and sex.

However, new research is showing that nicotine and cocaine are more similar than scientists ever realized.

In a recent study conducted by Danyan Mao, PhD, postdoctoral researcher at the University of Chicago Medical Center, a brain was sliced apart and exposed to levels of nicotine similar to those experienced by smoking a single cigarette. A few hours later, Mao looked for physical differences in the brain caused by the nicotine.

Sure enough, the usual changes to the bonds in the VTA showed up, but so did a surprise. The nicotine affected the D5 receptor in exactly the same way that cocaine does. The overlapping effects of the two drugs on the reward system of the brain may explain why both are highly addictive substances.

As you can imagine, there has been plenty of research done in order to find a way to get cocaine addicts to quit more easily. So this discovery could lead to new ways to get people to quit smoking as well.

The one caveat is that the best way to get people off cocaine is to block the D5 receptor. However, the only treatments we have developed that can do this also block the D1 receptor, which is vital for normal, healthy motivation, movement and pleasure.

Sure, you could block both of them to get people to quit cocaine and smoking. However, they would be empty, hollow shells of themselves incapable of feeling and love or joy in the world and very likely to end up committing suicide.